1/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <stdlib.h>
19#include <string.h>
20#include <unistd.h>
21
22char *
23getenv (const char *name)
24{
25 if (__environ == NULL || name[0] == '\0')
26 return NULL;
27
28 size_t len = strlen (name);
29 for (char **ep = __environ; *ep != NULL; ++ep)
30 {
31 if (name[0] == (*ep)[0]
32 && strncmp (name, *ep, len) == 0 && (*ep)[len] == '=')
33 return *ep + len + 1;
34 }
35
36 return NULL;
37}
38libc_hidden_def (getenv)
39

source code of glibc/stdlib/getenv.c